This page focuses on being safe while bikejoring.
Ha, ha , ha, safety? You have got to be kidding!
If you want to TRY to avoid injury, consider the following things:
TRAIN YOUR DOGS WELL. (covered elsewhere). More complete training gives you more control and certainty.
BE AWAKE AND ALERT. Most problems you encounter will be resolvable if you act correctly in around one or two seconds. Delay or make a mistake and very bad things happen shortly thereafter. If you bikejor when you aren't fully awake, you will find trouble.
Pay attention to your dogs, they may hear cars you can't see or hear. If your lead dogs ears suddenly swivel or it looks off the route, immediately figure out why. When your lead dog decides to do an emergency yield, pay attention. My dogs have saved our lives more than once by pulling over just before poorly driven cars have swung around corners onto the wrong side of the street and into our path.
WEAR a HELMET! Buy a really good helmet. ALWAYS WEAR YOUR HELMET, always!
I heard a doctor say "Brain injuries are forever". I believe it.
The straps on a helmet can make wind noise that makes cars hard to hear. Turn your head from side to side to both visually scan and hear vehicles in front and back.
You WILL be thrown off the bike, plan for it. Wear long sleeves, gloves, padding, etc. Figure out how you want to come off your bike and fall (roll).
WEAR GOGGLES. The dog's paws will throw debris in your face and on cold days the wind will blind you. Being blind on a fast moving bike will eventually result in a crash. Eye injuries are also bad, wear your goggles. If your dogs are slower, this will not be as essential, but if your dogs sprint at all, expect them to throw up debris.
BE VISIBLE! For low light situations I have made reflective vests for my dogs with blinking bike lights on them. I wear a reflective vest and have blinking lights on my bike. I have reflective tape on my bike. I have a powerful bike headlight that can be used as a spotlight. I also put light sticks on the dogs and have a backup headlamp on my helmet. Being called insane or mistaken for a low flying UFO is less painful than being hit by a truck.
ALWAYS HAVE BOTH HANDS ON THE HANDLEBARS, WITH ONE ON THE REAR BRAKE LEVER. Your dogs will likely be able to accelerate quickly enough that you can have the bike pulled out from under you. If they see a squirrel, you will loose control if you don't hang on with BOTH hands. If your dogs stop or slow suddenly, you must be able to apply the rear brake as fast as you can think. If any of the ropes go slack and get in the front wheel it will lock up and you will be thrown off the bike. Better to brake fast.
START WITH TWO DOGS MAX. I personally think that two dogs are often safer than one. But limit the dog power until you and your lead dogs are experienced. Don't increase the dog power beyond your abilities. If you have too much power you will be bouncing on the ground behind your dogs like a ball on a rope.
I and my experienced Samoyeds do well, and my brakes are of some use on the flat or uphill. Three Samoyeds make the brakes less useful on the flat, and four Samoyeds make the brakes irrelevant. When you lock the brakes and there is too much dog power, the bike either skids like an eraser or sort of bounces, depending on the surface. This assumes you can keep the bike upright and stay on it. Better to use fewer dogs. You can always run more dogs in shifts or switch to a bigger rig.
HAVE GOOD REAR BRAKES. The rear brake should be one you can lock up and skid on. My dogs can pull me along with the rear brake locked in many situations, but it does slow them down a bit.
DON'T USE THE FRONT BRAKE UNLESS DESPERATE. If you jam on the front brake you will be thrown from the bike. It is painful, trust me. I only use the front brake when my rear brake is locked or close to it, and only when I am desperate to slow down. I apply the front brake gradually and gently.
CARRY WATER, KEEP YOUR DOGS COOL AND HYDRATED. Your dogs normal body temperature is higher than yours (101F), they don't sweat, are wearing a fur coat, and 3/4 of their energy is released as heat, not movement. All this means that unless you keep your dogs temperatures ok and keep them hydrated, you will hurt or kill them.
CARRY A FIRST AID KIT. Things happen, and with dogs, accidents are more frequent.
Wear good gloves. Rope burn and road rash are both painful and unnecessary.
Have a mirror. Vehicles behind you are more dangerous than the ones in front. You know less about them, yet they will pass closer to you.
A helmet mounted mirror is easier to look in than a handlebar mounted mirror. I rubber band the mirror to my helmet, but still have to fix it periodically. The handlebar mounted mirrors break more often. On rough trails some mirrors will shake more than others. For me the helmet mounted mirror works better as I can keep my eyes on the dogs more. But having both types of mirrors can be nice.
I find that mushers who have multiple dogs always are watching the dogs instinctively. If someone talks to us, we answer, but we stare at the dogs. There are two reasons for this. If you watch the dogs you monitor their actions, and also their reactions to things you may not see, hear or smell. If you see a dog twitch its ears or put its nose down to catch a scent, something exciting may be about to happen. When all your dogs do this in unison, brace yourself. If you are looking elsewhere, for even a couple of seconds, you may miss the warning signs entirely.
Watch the dogs. They are your early warning system and they carry your fate.
If you are going on a longer trip, or are far from home, figure out how you'd evacuate a hurt dog and what vet you'd take them to. This is when you start thinking about a dog trailer that you can tow with your bike and start spending time looking on the web finding emergency vet clinics in the area you are traveling to. Make a plan before you go.